Set Parameter Event Publisher settings #591 (#614)

* Add ability to disable Parameter Event Publisher and change its QoS settings

Signed-off-by: RARvolt <rarvolt@gmail.com>

* address review comments

Signed-off-by: William Woodall <william@osrfoundation.org>

* use NodeOptions struct

Signed-off-by: William Woodall <william@osrfoundation.org>

* remove vestigial doc strings and improve docs

Signed-off-by: William Woodall <william@osrfoundation.org>

* fix lifecycle node constructor

Signed-off-by: William Woodall <william@osrfoundation.org>

rclcpp/include/rclcpp/node_interfaces/node_parameters.hpp

@@ -54,7 +54,9 @@ public:
     const node_interfaces::NodeClockInterface::SharedPtr node_clock,
     const std::vector<Parameter> & initial_parameters,
     bool use_intra_process,
-    bool start_parameter_services);
+    bool start_parameter_services,
+    bool start_parameter_event_publisher,
+    const rmw_qos_profile_t & parameter_event_qos_profile);
 
   RCLCPP_PUBLIC
   virtual

rclcpp/include/rclcpp/node_options.hpp

@@ -42,6 +42,8 @@ public:
    *   - use_global_arguments = true
    *   - use_intra_process_comms = false
    *   - start_parameter_services = true
+   *   - start_parameter_event_publisher = true
+   *   - parameter_event_qos_profile = rmw_qos_profile_parameter_events
    *   - allocator = rcl_get_default_allocator()
    *
    * \param[in] allocator allocator to use in construction of NodeOptions.
@@ -90,6 +92,9 @@ public:
 
   /// Set the arguments, return this for parameter idiom.
   /**
+   * These arguments are used to extract remappings used by the node and other
+   * settings.
+   *
    * This will cause the internal rcl_node_options_t struct to be invalidated.
    */
   RCLCPP_PUBLIC
@@ -106,6 +111,11 @@ public:
   initial_parameters() const;
 
   /// Set the initial parameters, return this for parameter idiom.
+  /**
+   * These initial parameter values are used to change the initial value
+   * of declared parameters within the node, overriding hard coded default
+   * values if necessary.
+   */
   RCLCPP_PUBLIC
   NodeOptions &
   initial_parameters(const std::vector<rclcpp::Parameter> & initial_parameters);
@@ -126,6 +136,10 @@ public:
 
   /// Set the use_global_arguments flag, return this for parameter idiom.
   /**
+   * If true this will cause the node's behavior to be influenced by "global"
+   * arguments, i.e. arguments not targeted at specific nodes, as well as the
+   * arguments targeted at the current node.
+   *
    * This will cause the internal rcl_node_options_t struct to be invalidated.
    */
   RCLCPP_PUBLIC
@@ -138,6 +152,15 @@ public:
   use_intra_process_comms() const;
 
   /// Set the use_intra_process_comms flag, return this for parameter idiom.
+  /**
+   * If true, messages on topics which are published and subscribed to within
+   * this context will go through a special intra-process communication code
+   * code path which can avoid serialization and deserialization, unnecessary
+   * copies, and achieve lower latencies in some cases.
+   *
+   * Defaults to false for now, as there are still some cases where it is not
+   * desirable.
+   */
   RCLCPP_PUBLIC
   NodeOptions &
   use_intra_process_comms(const bool & use_intra_process_comms);
@@ -148,10 +171,48 @@ public:
   start_parameter_services() const;
 
   /// Set the start_parameter_services flag, return this for parameter idiom.
+  /**
+   * If true, ROS services are created to allow external nodes to list, get,
+   * and request to set parameters of this node.
+   *
+   * If false, parameters will still work locally, but will not be accessible
+   * remotely.
+   *
+   * \sa start_parameter_event_publisher()
+   */
   RCLCPP_PUBLIC
   NodeOptions &
   start_parameter_services(const bool & start_parameter_services);
 
+  /// Return a reference to the start_parameter_event_publisher flag.
+  RCLCPP_PUBLIC
+  const bool &
+  start_parameter_event_publisher() const;
+
+  /// Set the start_parameter_event_publisher flag, return this for parameter idiom.
+  /**
+   * If true, a publisher is created on which an event message is published
+   * each time a parameter's state changes.
+   * This is used for recording and introspection, but is configurable
+   * separately from the other parameter services.
+   */
+  RCLCPP_PUBLIC
+  NodeOptions &
+  start_parameter_event_publisher(const bool & start_parameter_event_publisher);
+
+  /// Return a reference to the parameter_event_qos_profile QoS.
+  RCLCPP_PUBLIC
+  const rmw_qos_profile_t &
+  parameter_event_qos_profile() const;
+
+  /// Set the parameter_event_qos_profile QoS, return this for parameter idiom.
+  /**
+   * The QoS settings to be used for the parameter event publisher, if enabled.
+   */
+  RCLCPP_PUBLIC
+  NodeOptions &
+  parameter_event_qos_profile(const rmw_qos_profile_t & parameter_event_qos_profile);
+
   /// Return the rcl_allocator_t to be used.
   RCLCPP_PUBLIC
   const rcl_allocator_t &
@@ -191,6 +252,10 @@ private:
 
   bool start_parameter_services_ {true};
 
+  bool start_parameter_event_publisher_ {true};
+
+  rmw_qos_profile_t parameter_event_qos_profile_ {rmw_qos_profile_parameter_events};
+
   rcl_allocator_t allocator_ {rcl_get_default_allocator()};
 };
 

rclcpp/src/rclcpp/node.cpp

@@ -70,7 +70,9 @@ Node::Node(
       node_clock_,
       options.initial_parameters(),
       options.use_intra_process_comms(),
-      options.start_parameter_services()
+      options.start_parameter_services(),
+      options.start_parameter_event_publisher(),
+      options.parameter_event_qos_profile()
     )),
   node_time_source_(new rclcpp::node_interfaces::NodeTimeSource(
       node_base_,

rclcpp/src/rclcpp/node_interfaces/node_parameters.cpp

@@ -39,8 +39,10 @@ NodeParameters::NodeParameters(
   const rclcpp::node_interfaces::NodeClockInterface::SharedPtr node_clock,
   const std::vector<rclcpp::Parameter> & initial_parameters,
   bool use_intra_process,
-  bool start_parameter_services)
+  bool start_parameter_services,
-: node_clock_(node_clock)
+  bool start_parameter_event_publisher,
+  const rmw_qos_profile_t & parameter_event_qos_profile)
+: events_publisher_(nullptr), node_clock_(node_clock)
 {
   using MessageT = rcl_interfaces::msg::ParameterEvent;
   using PublisherT = rclcpp::Publisher<MessageT>;
@@ -52,12 +54,14 @@ NodeParameters::NodeParameters(
     parameter_service_ = std::make_shared<ParameterService>(node_base, node_services, this);
   }
 
+  if (start_parameter_event_publisher) {
     events_publisher_ = rclcpp::create_publisher<MessageT, AllocatorT, PublisherT>(
       node_topics.get(),
       "parameter_events",
-    rmw_qos_profile_parameter_events,
+      parameter_event_qos_profile,
       use_intra_process,
       allocator);
+  }
 
   // Get the node options
   const rcl_node_t * node = node_base->get_rcl_node_handle();
@@ -232,8 +236,12 @@ NodeParameters::set_parameters_atomically(
   }
 
   std::swap(tmp_map, parameters_);
+
+  // events_publisher_ may be nullptr if it was disabled in constructor
+  if (nullptr != events_publisher_) {
     parameter_event->stamp = node_clock_->get_clock()->now();
     events_publisher_->publish(parameter_event);
+  }
 
   return result;
 }

rclcpp/src/rclcpp/node_options.cpp

@@ -192,6 +192,32 @@ NodeOptions::start_parameter_services(const bool & start_parameter_services)
   return *this;
 }
 
+const bool &
+NodeOptions::start_parameter_event_publisher() const
+{
+  return this->start_parameter_event_publisher_;
+}
+
+NodeOptions &
+NodeOptions::start_parameter_event_publisher(const bool & start_parameter_event_publisher)
+{
+  this->start_parameter_event_publisher_ = start_parameter_event_publisher;
+  return *this;
+}
+
+const rmw_qos_profile_t &
+NodeOptions::parameter_event_qos_profile() const
+{
+  return this->parameter_event_qos_profile_;
+}
+
+NodeOptions &
+NodeOptions::parameter_event_qos_profile(const rmw_qos_profile_t & parameter_event_qos_profile)
+{
+  this->parameter_event_qos_profile_ = parameter_event_qos_profile;
+  return *this;
+}
+
 const rcl_allocator_t &
 NodeOptions::allocator() const
 {

rclcpp_lifecycle/src/lifecycle_node.cpp

@@ -77,7 +77,9 @@ LifecycleNode::LifecycleNode(
       node_clock_,
       options.initial_parameters(),
       options.use_intra_process_comms(),
-      options.start_parameter_services()
+      options.start_parameter_services(),
+      options.start_parameter_event_publisher(),
+      options.parameter_event_qos_profile()
     )),
   node_waitables_(new rclcpp::node_interfaces::NodeWaitables(node_base_.get())),
   use_intra_process_comms_(options.use_intra_process_comms()),